I would put Rash Guards as optional. In most cases, you can get away with rolling in sweater, jersey or hoodie and be covered (you just happen to create more handles for your training partner). However, if you do any sort of no-gi grappling on a serious basis (no-gi sessions at a dojo, or in competition) they are a must. Considering that you can get a decent rash Guard long sleeve for $20 to $30, it's not too much of an extra expense.
Hmmm... In a bit I'll throw up a listing with prices for everyone to look over.
It doesn't matter if you agree or disagree
... As long as I don't bore you and I spark a moment of thought, my goal is achieved
Queng leon queng tigre ecu tacacut, queca pa? - Pampangan Mandarigma Motto